When seeking information regarding the characteristics of an earth formation, such as, for example, the hydrocarbon content in the formation, a core sample may be obtained from the earth formation. The core sample may then be analyzed to determine the characteristics of the earth formation. Core samples may be obtained using coring tools. Coring tools conventionally include a core bit, which may include an inner bore and a cutting structure surrounding the inner bore. As the coring tool is driven into an earth formation, typically at the bottom of a previously formed borehole, the core bit may remove earth material around a core sample, which is received into the inner bore. A receptacle may be connected to the core bit, and may extend longitudinally above the core bit. The core sample may be received into the receptacle, and may be retained in the receptacle by a core catcher to keep the core sample within the receptacle as the core bit is withdrawn from the borehole.
In many cases, it may be desirable to alternate between coring operations and conventional drilling operations without tripping (i.e., removing) the drill string from the borehole. Accordingly, coring tools have been developed wherein the receptacle may be removed from the core bit by a wireline device, and a corresponding plug may be lowered by a wireline device and positioned concentrically within the inner bore of the core bit so as to plug the inner bore while the core bit is used to drill through the formation without coring. The corresponding plug may feature cutting structures positioned to engage and degrade the formation. The assembled core bit and plug may engage the formation and advance through the formation in a manner similar to a conventional drilling bit.